Root exudation facilitates water infiltration and rewetting of dry soil

The way plant roots facilitate water infiltration in soil may be just as important as the efficiency with which the root system in turn extracts it from the soil. Here we studied the mechanisms through which the root system facilitates water infiltration through a dry soil layer. Dye tracing experiments were conducted in model soil microcosms to characterise how root growth and exudation affects the permeability of dry layers of the model soil. Results showed that dissolved root exudates may be the primary facilitator of water infiltration, which may be linked to water surface tension. We conclude that in dry soil, root architecture and root exudation may combine to facilitate the infiltration of water and decrease the water lost by evaporation. These findings could enhance our understanding of the traits that provide drought resistance in crops.